The Magnacore self-drilling anchor’s hollow core allows cement grout to be poured into the ground while a micropile is installed
By Jim Timlick
An innovative micropile installation system designed for use on deep foundation stabilization projects with limited access has drawn rave reviews south of the border – and its U.S. supplier says its hoping to use it to crack the Canadian market in the not-too-distant future.
Intech Anchoring Systems introduced the Magnacore self-drilling anchor in the early 2000s. It’s a hollow bar, injection-bore micropile that offers an economical option for deep foundation work in challenging soil conditions.
Intech, with locations in St. Louis, Mo., and Livonia, Mich., supplies foundation and water-proofing products such as its Hydraway field drainage system to contractors across the U.S., with the bulk of its customers located in the central and eastern states. Although it has only a small presence in Canada at the moment, Intech’s national sales director says his company has an interest in expanding north of the border.
“Potentially, it’s a market we’re interested in,” said Bill Sears, who works out of the company’s St. Louis office. “There’s nothing definite on the radar right now, but we are looking to expand our footprint.”
Magnacore is a threaded micropile that features a hollow cavity. It comes in 3-metre lengths that can be coupled together to achieve any required depth.
It’s unique because it allows users to pump a high-pressure, cement grout mixture through its core while a pile is turned into the ground. The grout mixture is then pumped through the ports of a highly durable sacrificial bit located at the end of the micropile and into the surrounding ground. Once the user reaches the depth required for the project, they simply turn off the grout mixture supply and disconnect the pile from the rotary percussion drill that was used to install it. That’s much different than a conventional micropile system that requires an operator to drill a hole, insert a piece of casing into the ground, place a micropile inside the casing and then inject grout.
“Because you’re doing that all in one step with Magnacore, you are actually speeding up your installation and your hole is not going to collapse as you are drilling it,” Sears said. “You can drill and set everything in one pass as opposed to drilling, installing a piece of casing and then setting everything.”
Sears says Magnacore micropiles can be used for a variety of applications and are particularly suited for use on projects where there is weak soil to contend with or with limited access. It can also be used to install tieback anchors and soil nails.
“It’s pretty versatile,” he said.
In addition to speeding up installation in weak soil conditions where holes are more prone to collapse, Sears says the Magnacore system can save contractors money by reducing their labour costs: fewer rig operators are required and work is often completed quicker because of the all-in-one installation process.
Other advantages of the product are that it is user-friendly and requires very little training to get started, says Sears.
“It doesn’t take a tremendous amount of training,” he said. “Usually, if you’ve got an experienced person that’s used a drill before, we can sit down with them and in a matter of a day, have them comfortable with drilling the elements. The biggest challenge – because you’re pumping grout at the same time as drilling – is the coordination between the drill operator and the person that is keeping the grout plant moving. Those two people have to work in unison.”
Magnacore is manufactured for Intech in the U.S. and is run through a series of rigorous tests prior to shipping to the company’s warehouse. That includes a preliminary test before it leaves the manufacturer, a mill certification process to ensure it meets the company’s specifications and a follow-up test to ensure the material is performing as expected. Intech publishes the yield strengths of the product on their website.
“We feel very confident that the quality is there,” Sears said of Intech’s testing procedures.
One of the beauties of the Magnacore system is that it doesn’t require much in terms of installation equipment. A relatively small drill, such as a rotary percussion drill with a feed system, can be attached to a skid-steer loader or excavator to install the piles.
Magnacore’s ease of use on worksites with limited access, which Sears calls one of its key benefits, is one of the main reasons it was recently used on a challenging slope stabilization project on a toney estate in Washington, in the Pacific Northwest of the U.S.
A contractor who specializes in slope stabilization work was hired to prevent rocks on a nearby hillside from rolling down onto a nearby home and surrounding property. The contractor, who doesn’t want to be identified because of privacy concerns, installed Magnacore micropiles into the hillside and then attached a heavy-duty, above-ground screen to prevent loose rocks from rolling all the way to the bottom of the hill. Making it even more challenging was that the contractor used a proprietary technology that required no large cuts into the hillside to avoid any environmental or cosmetic damage. Some slope stabilization work requires a large number of cuts and multiple tiers.
Adding to the degree of difficulty of the project was the geological landscape of the hillside. As is the case in many parts of the region, it contains a large amount of glacial till, or rocky materials left behind by the movement of a glacier. The contractor used a tri-bit blade supplied by Intech and reported no issues with it, Sears says, adding the project wrapped up on time earlier this past summer.
Thankfully, the coronavirus pandemic had virtually no impact on the completion of the hillside stabilization project. Test numbers in the region were relatively low, meaning work on the project was allowed to proceed uninterrupted. In addition, Intech Anchoring stores a large amount of Magnacore products at its U.S. warehouse, which Sears says meant there were no supply chain issues.
Intech only recently started working with the contractor and Sears says all of the comments his company has received from them regarding Magnacore have been positive. 